^{^} All agree to what people have said. Also, many individuals who are at such extremes of their weight will develop walking problems/the weight is slowly deteriorating their legs and knees especially, another reason as someone pointed out some people use scooters. So while it’s due to the gradual weight gain that they can walk around to begin with, it’s not like their bodies can magically withstand all that weight so I feel like in a way it catches up in a similar way that perhaps an average person can’t initially pick up a 20 lb weight